update generator for multi range request
update generator for multi range request

cern-it-sdc-id/davix,cern-it-sdc-id/davix,EricKTCheung/davix,cern-it-sdc-id/davix,cern-it-sdc-id/davix,EricKTCheung/davix,EricKTCheung/davix,EricKTCheung/davix